Vacuum packaging provides an efficient method of packaging many products, including foodstuffs. The use of vacuum packaging can increase the shelf like of packaged foodstuffs by removing the air from the packaging, as well as reducing the volume of the packaged product.
Many individual machines are available to assist in the vacuum packaging of products, from a variety of sources. Each of these machines follows a basic pattern: product is placed within packing material, which is often a thermo-formable plastic film, air is evacuated from the within the packing material, and the packing material is sealed around product.
In order for commercially significant amounts of vacuum packaged product to be efficiently produced, mass production equipment has been developed by vendors to implement vacuum packaging on a mass scale. Such equipment typically follows several stages, which include a stage for placing product within packaging, loading the product/packaging combination into a vacuum chamber, drawing a vacuum in the vacuum chamber to remove air from the packaging, using a heated bar to melt edges of the packaging together to seal the package, trimming the packaging materials to minimize packaged product volume, and placing the packaged product onto a conveyor for aggregation into further containers.
Drawing the vacuum in the package tends to take the greatest amount of time, as vacuum pumps are typically used to reduce the air pressure in the vacuum chamber. Accordingly, mass production equipment may use a carousel of vacuum chambers to increase the utilization time for drawing a vacuum in each vacuum chamber.
The vacuum chamber itself may be formed from two components, commonly referred to as the platen and the chamber cover, with the platen forming the stage or platform on which product in unsealed packaging is placed, and the chamber cover forming an air tight cover over the platen after product has been placed on the platen. The combined platen/chamber cover may typically also be provided with an air-tight connection for connecting the combined chamber cover/platen (when combined referred to as the “vacuum chamber”) to one or more vacuum pumps for drawing air from the vacuum chamber, and thereby from within the packaging containing the product at the same time. The vacuum chamber may additionally be provided with a means for sealing the packaging under vacuum, such as a heated metal element for melting the packaging to form a seal to prevent air from re-entering the packaging when the package is removed from the vacuum chamber.
In order to address the longer “stay time” of the vacuum chamber during the vacuum stage, multiple vacuum chambers are typically implemented, often from different platen and chamber cover combinations. The ability of the vacuum chambers to hold a vacuum is critical to the efficiency of the machine in packaging product, i.e., product which is not subjected to an adequate vacuum prior to sealing may need to be rejected, resulting in wastage. Detection of sealing problems is critical. Having sealing problems can result in large amounts of sub-standard product being distributed to consumers or being wasted as a result of rejection, prior to a problem being discovered, and may also result in significant down time for the product equipment in order for deficiencies to be diagnosed and corrected.